My use case is:
Questions:
Will iClould keep user's data that was belonging to the deleted app? (Based on my experiment, the data is kept on iCloud when my App is deleted, however, I am not sure whether the behaviour is official).
If the answer is Yes, then I have the following questions:
a. How user's data eventually get deleted/cleared from user's iCloud storage? (My concern is that if the user decide never to use my app again, the data would become useless therefore should be cleared on iCloud to free spaces)
b. If user decide re-download my app, how can he get access to the data iCloud he originally uploaded?
c. Can I manage the user's data from iCloud web portal (www.icloud.com)? I don't see my uploaded document appears in iCloud web portal, even I put my files under "Documents" subfolder.
d. Is there any official documentation that describes this behavior?
Thanks in advance!
Yes, iCloud will keep a person's data belonging to the deleted app by default.
Follow up questions
A: The data will stay in iCloud storage until the person decides to delete the data. Using the Settings app, a person can manage their iCloud storage, down to turning off backups of each app's storage. Or the entire backup for a device can be deleted to start over with a fresh backup.
B: If a person reloads an app on their iOS device, meaning any app with the exact same App ID so it could be an updated version, iCloud should restore the data from the app's backup.
C: No, the iCloud Web portal only gives access to the apps loaded by Apple, currently Mail, Contacts, Calendar, Find My iPhone, and iWork. Apple could offer the ability to add apps to the iCloud Web portal, just like we add apps to our iOS and Mac devices. But that would be some future offering.
D: Much of this is documented in the developer documentation. Some of this answer is undocumented, and gleaned from experimenting with iCloud (so please correct me where I'm wrong).